I've noticed that when using Foobar2000 through the virtual cable, that the cable control panel's Input statistic stays below 512 consistently, even when opening the browser, for instance, as long as I use DS or WASAPI Push to send to the cable, but if I use WASAPI Event, it uses some buffers in the b1024 area.

I am using the 1536 Max Latency setting and WASAPI Push with this player since the preceding is the case.

What is the actual difference between DS vs WASAPI Event vs WASAPI Push and why the big difference when using WASAPI Event?

Audio buffering is pending on the player/recorder application and the method they use to manage audio devices.

Normally using WASAPI allows having a fixed size buffering between the client application and the audio device... but using WASAPI Shared mode could change this rule i guess... With MME the system can send various size buffer, also pending on used amplerate... DS is comparable to MME using possibly fixed size buffer, but generally around 1024 samples or more...

Well, this is why i've made a default configuration able to work in most of situation. If you optimize VB-CABLE internal latency, it can work with a given application, using a given samplerate, and does not work anymore with another application or another samplerate. and statistics in the VB-CABLE control panel are there to understand these possible buffering problems.

if you are using a 1536 sample buffer latency, and considering that internal Sample rate is the same than audio point ones. Client Application audio buffering must use 512 sample buffer size max (if it goes above, you will possibly get a cut in the sound)

Obviously I am trying to keep my latency as low as possible. Ultimately this is all directed at trying to get a keyboard's virtual instrument latency or my ASIO input's latency as low as possible for live performance and recording. All this information is helping me get a clearer idea of what my options are.